Available only to registered Mac developers, build 12A178q of Mountain Lion comes with a laundry list of fixes and minor tweaks. The release notes also list the known issues that are still being worked on by Apple (including issues with both Quicktime and Game Center) and directions for developers to submit bug reports as they explore the new build.

Mac OS X 10.8 Mountain Lion (read our first take from February) is expected to be launched to the public sometime this summer, only one year after the release of OS X Lion, making it Apple's fastest major OS update so far, and requiring a faster turnaround on fixes than ever before.

Check back with CNET for more information about Mountain Lion as the release date draws closer this summer.